Stroke - Cerebrovascular event Flashcards
What is a stroke?
Clinical syndrome caused by disruption of blood supply to the brain, characterised by rapidly developing signs of focal or global disturbance of cerebral functions, lasting for more than 24 hours or leading to death
What are the 2 main types of stroke?
- Ischaemic stroke (85%)
- Haemorrhagic stroke (15%)
What is meant by ischaemic stroke?
Ischaemic strokes occur when blood supply in a cerebral vascular territory is reduced due to stenosis or complete occlusion of a cerebral artery
What are the 5 TOAST classified causes of ischaemic stroke?
- Large vessel atherosclerosis (50%) - TOAST1
- Intracranial small vessel atherosclerosis (25%) - TOAST3
- Cardio-embolic (20%) - TOAST2
- Other (5%) - TOAST4
- Unknown - TOAST5
Give an example of a large vessel atherosclerotic cause of stroke
Carotid artery stenosis
What are some cardio-embolic causes of stroke?
- Atrial fibrillation
- Endocarditis
- Valvular heart disease
What re some rarer causes of stroke?
Vasculitis
Non-inflammatory vasculopathy
genetic microangiopathies
Parainfectious
Haematological causes
Other
What are some non-inflammatory vasculopathies that can cause stroke?
- Dissection
- Moya-Moya angiopathy
- Metabolic (Fabry disease, homocystinuria)
- Carotid artery web
What are some genetic microangiopathies?
CADASIL, CARASIL, MELAS (SUSAC syndrome is non-genetic)
What are some parainfectious causes of stroke
Covid
HIV
What are some haematological causes of stroke?
- Primary - Antiphospholipid syndrome
- Secondary - Cancer, TTP, IBD
What are some drugs that can cause stroke?
Contraceptives, cocaine, heroin
What are some pregnancy related causes of stroke?
Eclampsia, pre-eclampsia
What are some other embolic causes of stroke (Not cardio-embolic)
Fat embolism
Air embolism
Tumour embolism
What is haemorrhage stroke?
Haemorrhagic stroke occurs when there is rupture of a cerebrospinal artery, with most being due to a primary haemorrhage or subarachnoid haemorrhage
What are some causes of primary haemorrhage in haemorrhage stroke?
Hypertensive, caused by cerebral amyloid angiopathy or rupture of an aneurysm
What are some causes of young stroke (<50)?
Patent foramen ovale or arterial dissection (Identified by TTE with bubble or transcranial doppler)
What are some risk factors for stroke?
- Hypertension
- High BMI
- High fasting glucose
- Air pollution
- Smoking
- Poor diet
- High LDL cholesterol
- Kidney dysfunction
- Alcohol use
- Sedentary lifestyle
Which brain hemisphere is dominant?
Left
What is a common symptom of dominant (left) hemisphere cortical event?
Language dysfunction
What is a common symptom of non-dominant (Right) hemisphere cortical event?
Spatial awareness dysfunction
What are the 2 regions of affected brain tissue in stroke?
Ischaemic core
Penumbra
What is the ischaemic core?
The area of brain which has developed necrosis (Cerebral blood flow < 20%)
What is the penumbra?
The region of tissue around the area with reduced cerebral blood flow, but is getting a supply of O2 and glucose from collateral arteries
This can progress to infarction, but is still salvageable
What is the ischameic cascade?
This is a series of biochemical reactions that are initiated in the brain and other aerobic tissues after seconds to minutes of ischaemia
What is the ischameic cascade that occurs in ischaemic stroke?
- Switch from aerobic to anaerobic metabolism
- Accumulation of lactic acid
- Na/K channel dysfunction
- Na/Ca channel dysfunction
- Mitochondrial apoptotic factor release
What is caused in tissue by Na/K channel dysfunction?
Cytotoxic oedema
What is caused in tissue by Na/Ca channel dysfunction?
- Excitotoxicity
- Degradative enzymes
- Formation of radicals
What changes occur to the blood brain barrier in ischaemia?
- Endothelial swelling
- Inflammatory response leading to astrocytic foot contact being lost from endothelial cells
- No mediated
- Vasogenic oedema starts 4-6 hours after ischaemia, which can lead to haemorrhagic transformation through extravasation of blood
What are the main symptoms of stroke?
Stoke symptoms are typically asymmetrical:
- Sudden weakness of limbs
- Sudden facial weakness
- Sudden onset dysphasia (speech disturbance)
- Sudden onset visual or sensory loss
What is FAST?
- Face - Fallen on 1 side
- Arms - Unable to lift arm
- Speech - Slurred or absent
- Time - Time to call 999
What are the 4 Oxford classifications of stroke?
TACS - Total anterior circulation syndrome
PACS - Partial anterior circulation syndrome
POCS - Posterior anterior circulation syndrome
LACI - Lacunar infarctions
What is total anterior circulation syndrome (TACS)?
This is alarge cortical strokeaffecting the areas of the brain supplied by both themiddleandanteriorcerebralarteries
What are the 3 diagnostic criteria of TACS?
- Contralateral hemiplegia or hemiparesis, AND
- Contralateral homonymous hemianopia, AND
- Higher cerebral dysfunction (e.g. aphasia, neglect)
What is the prognosis of TACS?
Most severe type of stroke with only 5% of patients being alive and independent at 1 year
What is partial anterior circulation syndrome (PACS)?
This is aless severe form of TACS, in which onlypartof theanterior circulationhas been compromised
What are the diagnostic criteria for PACS?
- 2 out of the 3 features present in a TACS OR
- Isolated cortical dysfunction such as dysphagia OR
- Pure motor/sensory signs less severe than in lacunar syndromes (e.g. monoparesis)
What is posterior circulation syndrome (POCS)?
This involves damage to the area of the brain supplied by theposteriorcirculation
This Involves the vertebrobasilar arteries and associated branches (supplying the cerebellum, brainstem, and occipital lobe)
What is the diagnostic criteria for POCS?
Defined by 1 of the following:
- Cerebellar dysfunction, OR
- Conjugate eye movement disorder, OR
- Bilateral motor/sensory deficit, OR
- Ipsilateral cranial nerve palsy with contralateral motor/sensory deficit, OR
- Cortical blindness/isolated hemianopia
What are lacunar infarctions (LACI) ?
These are small infarcts around the deeper parts of the brain (basal ganglia, internal capsule, thalamus and pons) caused by occlusion of a single deep single penetrating artery
What is the diagnostic criteria of LACI?
- Pure motor stroke OR
- Pure sensory stroke OR
- Sensorimotor stroke OR
- Ataxic hemiparesis
There should be NO: visual field defect, higher cerebral dysfunction, or brainstem dysfunction
What is the prognosis of LACI?
Best prognosis of all the strokes with 60% of patients alive and independent at 1 year
What is the ROSIER stroke classification?
A clinical scoring tool based on clinical features and duration - used to recognise stroke in the ER
What are some scoring systems used in stroke?
ROSIER
NIHSS (National institute of Health stroke score)
What does an NIHSS score of 1-4 show?
Mild stroke
What does an NIHSS score of 5-15 show?
Moderate stroke
What does an NIHSS score of 16-20 show?
Moderate-Severe stroke
What does an NIHSS score of 21-42 show?
Severe stroke
What categories are score in the NIHSS?
What is the initial investigation required in stroke?
CT head should be performed on arrival to the emergency department to distinguish ischaemic from haemorrhagic stroke
What investigation is required if thrombectomy may be indicated?
CT contract angiography
Describe the treatment pathway of ischaemic stroke
- Urgent imaging
- Thrombolysis or thrombectomy
- Blood pressure lowering
- Stroke unit care
- Swallow assessment, nutrition and hydration
- Secondary prevention medication
- DVT prevention
What drug is used for thrombolysis of stroke patients?
Altepase (Tissue plasminogen activator)
In whom is thrombolysis indicated?
Patients presenting within4.5 hours of symptom onsetand with no contraindications to thrombolysis
In whom is thrombectomy indicated?
Patients with anterior circulation strokes within 6 hours of symptom onset, provided that they have a good baseline functional status and lack of significant early infarction on initial CT scan
OR
posterior circulation strokes up to 12 hours after onset
What arteries can thrombectomy be performed in?
- Carotid artery
- Middle cerebral artery
- Some M2 branches
- Basilar artery
What are the 2 main forms of thrombectomy?
Stentriever
Aspiration catheter
What is Stentriever thrombectomy?
Using a stent which is inflated within the clot, trapping the clot and then removing it
What is aspiration catheter thrombectomy?
A suction tube is inserted to the clot and mild suction is applied to move out the clot
What drugs are used for acute blood pressure lowering in stroke?
IV labetalol or IV GTN
Why is stroke unit care important?
For every 33 patients treated in a stroke unit, there is 1 extra survivor
What is the mainstay of treatment for haemorrhagic stroke?
Treatment essentially supportive
In who is decompressive craniotomy performed?
Perform within 48 hours in MCA strokes causing infarction of more than 50% of the MCA territory
MCA = Middle cerebral artery
Describe the pathway of swallow therapy in stroke patients
- Patients on arrival are given an initial swallow screen
- If this is found to be abnormal, a speech and language therapist will provide further assessment
- NG tube or thickened fluids may be required
What is the purpose of physiotherapy in stroke treatment?
Help prevent spasticity and contractures, and teach patients how to cope with their current level of function
What are some required secondary prevention measures in stroke?
- Anti-thrombotic therapy (Not in haemorrhagic)
- Statins
- Diabetic control
- Smoking cessation
Describe the antiplatelet therapy regime in those with an NIHSS under 4
- Aspirin 300mg stat + Clopidogrel 300mg stat
- 75mg of both daily for 3 weeks
- Continuous 75mg clopidogrel for life
Describe the antiplatelet therapy regime in those with an NIHSS over 4
- Aspirin 300mg stat + 300mg clopidogrel stat
- 300mg Clopidogrel daily for 2 weeks
- Clopidogrel 75mg daily for life
What are some DVT prevention measures used in stroke care
- Heparin (including LMWH) reduces DVT risk but benefit is outweighed by bleeding risk
- Intermittent pneumatic compression reduces risk of DVT compared to control (CLOTS 3 trial)
Give the timeline of complications in stroke
What are some possible acute complications of stroke?
- Malignant MCA syndrome
- Obstructive hydrocephalus
- Haematoma expansion after ICH
- Aspiration pnuemonia
- Dehydration/electrolyte impairments/AKI
- DVT/Pes
- Recurrent strokes
What is malignant MCA syndrome?
Rapid neurological deterioration due to the effects of space occupying cerebral oedema following middle cerebral artery (MCA) territory stroke.
Describe the presentation of malignant MCA syndrome
Tends to occur 2-5 days post stroke, but can be <24 hours
Generally problematic in younger patients
Approx 80% mortality
How is malignant MCA syndrome managed?
Treatment option is hemicraniectomy (Removal of some of the cranium to decrease pressure) however, patients may still be left with significant disability
What is shown?
Hemicraniectomy in malignant MCA syndrome
How can stroke cause obstructive hydrocephalus?
Posterior fossa infarcts like large cerebellar infarcts
Intraventricular haemorrhage with occlusion of 4th ventricle
What is shown?
Obstructive hydrocephalus
What are the 2 main forms of post-stroke pneumonia
Aspiration
Hypostatic
How does stroke cause pneumonia?
Immunosuppression secondary to stroke
Dysphagia
What are some management options to prevent post-stroke pneumonia
- Good oral hygiene
- Good positioning during NG feeding
- Dysphagia management
- Early treatment of infection
How can carotid artery disease cause stroke?
The carotid artery supplies most of the blood supply to the brain, and so atherosclerosis of the carotid artery can cause either reduced blood flow to the brain or embolism to the brain
What are some symptoms of carotid artery disease?
- Higher cortical dysfunction (Aphasia, dysgraphia, apraxia)
- Amaurosis fugax
- Chronic ocular ischaemia syndrome
- Upper/lower limb clumsiness
What investigations are required in carotid artery disease?
- Carotid artery duplex scan
- CT angiography
- MR angiography
Is asymptomatic carotid artery disease treated in the UK?
NO
What is the main treatment for carotid artery disease?
Carotid endarterectomy
What is carotid endarterectomy?
A surgery in which the carotid artery is opened up, the atherosclerotic plaque is removed and the artery is closed with a patch
How is the carotid artery accessed during surgery?
- Incision along the anterior border of the sternocleidomastoid
- Division of platysma
- Retraction of the internal jugular vein
- Control of the common carotid artery, carotid bulb and branches
Describe the procedure of carotid endarterectomy once the carotid artery is accessed?
- Heparin
- Shunting of the carotid artery
- Endarterectomy
- Patch repair with bovine pericardium
- Flushing
- Shunt removal
- Closure of the surgical site
In whom is carotid endarterectomy performed?
Carotid endarterectomy is only performed in those with >70% artery blockage
What are some possible complications of carotid endarterectomy?
- MI
- Bleeding
- Infection
- Nerve damage
- Death
What may be offered to patients with symptomatic carotid artery disease if they cannot undergo endarterectomy?
Carotid artery stenting
